On October 22, 2014, SunShot awarded more than $14 million to 10 research institutions to meet or exceed SunShot targets by improving performance, efficiency, and durability of solar PV devices. The R&D projects will explore a spectrum of leading-edge solutions, from new high-performance materials like perovskites to novel techniques for creating solar cells with high efficiency and lower manufacturing cost.

AWARDEES

DUKE UNIVERSITY

Location: Durham, NC

Award Amount: $1,300,002

Principal Investigator: Dr. David Mitzi

Project Summary: This project will address several areas to support the development of Pb-halide-based perovskites in order to make such devices more suitable for commercialization: 1) The device efficiency at the cell level will be optimized in order for the promise of an ultra-low-cost technology to be realized, 2) lead (Pb) replacement will be pursued, and 3) the stability of the materials / devices towards moisture, air and temperature will be established and improved.

SANDIA NATIONAL LABORATORIES

Location: Livermore, CA

Award Amount: $1,354,245

Principal Investigator: Mark Allendorf

Project Summary: This project will develop novel absorbers and photovoltaic cell architectures that maximize the performance of single-junction dye-sensitized solar cells (DSSC). Sandia will develop a new materials construct, in which nanoporous Metal-Organic Frameworks (MOFs) and TiO2 architectures are combined with semiconductor interlayers and controlled interfaces formed by atomic layer deposition (ALD) methods to address key limitations of DSSCs. Issues to be addressed include increased light harvesting, energy losses at the working electrode, and charge recombination.

STANFORD UNIVERSITY

Location: Stanford, CA

Award Amount: $1,484,623

Principal Investigator: Micheal McGehee

Project Summary: This project will develop and deposit thin films of perovskite semiconductors with band gaps ranging from 1.6 to 2.3 eV on top of silicon solar cells to advance cell efficiency and reduce cost. The project will improve the solar cells by optimizing film deposition conditions to reduce defects and obtain the best crystal size and orientation. The open circuit voltage (VOC) of the perovskite junction will be improved by optimizing the contact energy levels. As the reliability of the perovskite material is a significant risk to the commercialization of such devices, this project will determine the primary degradation mechanisms of perovskite devices. Accelerated tests will also be performed to quantify permissible limits of water and oxygen exposure.

THE REGENTS OF THE UNIVERSITY OF MICHIGAN

Location: Ann Arbor, MI

Award Amount: $1,350,000

Principal Investigator: Stephen Forrest

Project Summary: This project will advance the practical viability of organic photovoltaics (OPV) by demonstrating reliable, large area and high-efficiency organic multijunction cells based on small molecule materials systems. The implementations in academic labs will be transferred to their commercialization partner, NanoFlex Power Inc., who will work with manufacturers to achieve rapid acceptance and deployment of OPV technology. The goals of this proposed program are: 1) demonstration of multijunction organic solar cells with efficiencies of >18%, 2) demonstration of extrapolated multijunction cell lifetimes exceeding 20 years, 3) demonstration of ultra-rapid organic film deposition on continuous rolls of foil substrates using our proprietary technology of organic vapor phase deposition; and 4) demonstration of roll-to-roll (R2R) application of package encapsulation.

NATIONAL RENEWABLE ENERGY LABORATORY (MANAGED AND OPERATED BY THE ALLIANCE FOR SUSTAINABLE ENERGY, LLC)

Location: Golden, CO

Award Amount: $1,500,000

Principal Investigator: Adele Tamboli

Project Summary: Integration of semiconductors comprised of Group 3 and Group 5 elements (III-V) with silicon (Si) has proven to be challenging due to lattice mismatch, thermal expansion mismatch, and antiphase domains associated with growth of a lower symmetry material on a higher symmetry material, deteriorating both the Si and III-V cell performance. This project will mitigate these issues by incorporating a nanopattered buffer layer between the Si and III-V materials, resulting in a low-cost method for selective area growth of lattice mismatched triple junction solar cells. Nanoimprinted buffers will: 1) reduce defect density in the top cell and on the Si interface, 2) preserve excellent Si interface passivation, and 3) may provide a platform to integrate nanophotonic light management for enhanced cell performance. This project will develop nanopatterning and growth techniques that are compatible with industrial PV manufacturing to integrate III-V materials and Si for high efficiency solar cells.

NATIONAL RENEWABLE ENERGY LABORATORY (MANAGED AND OPERATED BY THE ALLIANCE FOR SUSTAINABLE ENERGY, LLC)

Location: Golden, CO

Award Amount: $1,360,000

Principal Investigator: Kai Zhu

Project Summary: This project has three major objectives: 1) develop high-efficiency single-junction perovskite (top and bottom) solar cells; 2) obtain an understanding of basic material (e.g., doping and defect) and device properties related to halide perovskites; and 3) demonstrate ultra-high efficiency tandem thin-film devices based on halide perovskites. Specific targets are to achieve 1) >20% for low-bandgap (0.9–1.4 eV) bottom cells and >15% for wide-bandgap (1.7–1.9 eV) top cells, and 2) >25% for dual-junction tandem cells, under 1-sun illumination. To achieve these targets, two complementary methods (solution processing and co-evaporation deposition) will be used. Theoretical modeling will be conducted to understand doping/defect physics for perovskites. Information learned on doping physics, defect chemistry, and device modeling will be made available to the photovoltaic community and will support solar manufacturers and start-ups looking for their next-generation PV products.

NATIONAL RENEWABLE ENERGY LABORATORY (MANAGED AND OPERATED BY THE ALLIANCE FOR SUSTAINABLE ENERGY, LLC)

Location: Golden, CO

Award Amount: $1,500,000

Principal Investigator: Aaron Ptak

Project Summary: This project is developing a InGaAsP/Si (indium gallium arsenide phosphide / silicon) tandem photovoltaic technology that leverages extremely high efficiency devices and low-cost, high-throughput methods to meet and exceed cost targets. Awardees will conduct controlled liftoff of III-V devices grown on Ge substrates with attention toward device quality, substrate reuse, and manufacturability, while also developing a low-cost, high-throughput growth of highly efficient III-V solar cells with the optimal bandgap to achieve the maximum efficiency from a two-junction structure. Furthermore, awardees will attempt a proof-of-concept integration to illustrate that this technology is capable of achieving >30% conversion efficiency.

UNIVERSITY OF NEBRASKA-LINCOLN

Location: Lincoln, NE

Award Amount: $1,211,075

Principal Investigator: Jinsong Huang

Project Summary: This project is developing tandem junction solar cells with organo-lead trihalide perovskites based on high-efficiency perovskite cells as the top cell, and c-Si cells as the bottom cell. Awardees are creating a novel top cell system that is compatible to the bottom high-efficiency c-Si solar cell. The novel design will boost the power conversion efficiency (PCE) of silicon solar cells over 30% under air mass (AM) 1.5 spectrum with minimal cost increases.

UNIVERSITY OF HOUSTON

Location: Houston, TX

Award Amount: $1,499,994

Principal Investigator: Dr. Venkat Selvamanickam

Project Summary: This project is working to achieve a drastic reduction in the cost of III-V solar cells through a combination of high efficiency and low manufacturing cost. Awardees are depositing III-V thin films on inexpensive flexible metal substrates by all roll-to-roll (R2R) processing.